Centralizer

ABSTRACT

A centralizer and more particularly a centralizer utilized for supporting and guiding a drill steel along the drill guide frame of a track or similar type rock drill.

United States Patent [1 1 Bailey et al.

[4 1 Apr. 30, 1974 CENTRALIZER Inventors: Edward A. Bailey, R.F.D. No. 2 Box 37, Newport, NH. 03773; Robert E. Wolcott, Green Mountain Rd., Claremont, NH. 03743 Filed: Oct. 2, 1972 Appl. No.: 293,793

US. Cl. 308/39 Int. Cl. E21c 11/02 Field of Search 308/39; 92/136, 138;

References Cited UNITED STATES PATENTS 3/1956 Hefner 92/136 12/1953 Gillerstrom 308/39 2,844,128 7/1958 Steiner 92/136 FOREIGN PATENTS OR APPLICATIONS 777,300 6/1955 Great Britain 308/39 Primary Examiner-Charles J. Myhre Assistant Examiner-R. H. Lazarus ABSTRACT A centralizer and more particularly a centralizer utilized for supporting and guiding a drill steel along the drill guide frame of a track or similar type rock drill.

8 Claims, 4 Drawing Figures Wit-1mm 30 m4 3,807,812

sum 2 or 2 CENTRALIZER Rock drill assemblies and especially rock drill assemblies which are adapted to support a drill string in excess of ten feet on the respective guide frame thereof provide means thereon to support and guide the drill string at a point intermediate the forward end centralizer and the drill motor. I-leretofore various intermediate centralizers have been provided which were slidable along the drill guide frame in response to the posi tion of the drill rod. Such a prior intermediate centralizer limited the forwardmost movement of the drill motor for when the drill motor had advanced to the for wardmost end of the guide frame the intermediate centralizer was located intermediate the forward centralizer and the drill motor.

By means of the present invention which includes a centralizer adapted to swing out of the path of the drill motor thereby permitting the drill motor to advance therepast, the hereinabove mentioned feed limitation is overcome. Furthermore the centralizer assembly of the present invention is of a relatively uncomplicated structure and is pneumatically or hydraulically operable.

These and other objects and advantages of the present invention will become more readily apparent upon a reading of the following description and drawings in which: I

FIG. 1 is a schematic illustration of a rock drill assembly incorporating a centralizer assembly of the present invention;

FIG. 2 is a side elevational view, partly in section, of a centralizer assembly constructed in accordance with the principles of the present invention;

FIG. 3 is a longitudinal cross-sectional view of the centralizer assembly taken on lines 3-3 of FIG. 2; and

FIG. 4 is a transverse cross-sectional view of the centralizer assembly taken on lines 4-4 of FIG. 2.

A drilling apparatus includes a drill guide frame 12 supported and rendered movable over a surface by a crawler support 14 of a type well known in the art. Guide frame 12 is suitably supported by a well known boom assembly 16. Boom assembly 16 includes the usual extensible cylinder 18 and 19 for swinging guide frame 12 in the vertical and horizontal direction, respectively. Guide frame 12 supports a drill motor 20 thereon, which motor 20 is axially movable with respect to guide frame 12 by any suitable means: for example, a cable feed arrangement as is illustrated in U. S. Pat. No. 3,667,552.

Drill motor 20 receives a drill rod 22 in the forward chuck end thereof. Rod 22 extends forwardly from motor 20 along guide frame 12 and is supported and centered along the longitudinal extent with respect to guide frame 12 by means of forward and intermediate centralizers 24 and 26, respectively. As shown centralizer 24 is of the more or less standard construction and centralizer 26 is constructed in accordance with the principles of this invention. It is to be noted, however, that it is contemplated that forward centralizer 24 could additionally be constructed in accordance with the principles of this invention.

Inasmuch as the invention herein resides in the structure and operation of centralizer 26 and the balance of the elements set forth hereinabove are generally well known in the art, further description of such elements I will not be set forth except as necessary in the description of the preferred embodiment of centralizer 26.

Centralizer 26 comprises a stationary casing member 28 which is suitably secured to guide frame 12 and a centralizer arm 30 which is supported by member 28 in a manner that arm 30 is rotatable about a vertical axis with respect to a horizontal longitudinal axis of member 12 all in a manner as is hereinafter described in detail.

As best shown in FIGS. 3 and 4, casing member 28 includes: a T-shaped mounting portion 32; an upwardly opened generally U-shaped intermediate portion 34 rigidly secured to the stem of portion 32 and extending outwardly therefrom; and generally cylindrical piston head receiving portions 36 suitably sealingly and releasably secured to intermediate portion 34 at respective axial ends thereof and extending axially outwardly therefrom. The flange of mounting portion 32 is suitably secured, such as by bolts 38, to a side of guide frame 12 in a manner such that portion 32 is below the upper side of guide frame 12 thereby allowing the drill motor 20 to pass thereby along frame 12 without interference. For purposes of the hereinafter set forth description axially shall be considered parallel to the longitudinal extent of frame 12; and vertically and upwardly and downwardly shall be considered with respect to the top and bottom flanges of frame 12 as viewed in FIG. 4.

Casing member 28 additionally includes a centralizer arm supporting portion 40. Portion 40 comprises a generally cylindrical receiving section 42 having a vertically extending bore 44 therethrough; a radially outwardly extending centralizer seat 46 adjacent the upper end of section 42; and an outwardly extending flange 48 intermediate the axial ends of section 42. In the final assembly of centralizer 26, intermediateflange 42' is suitably sealingly secured over the upper open end of intermediate portion 34 by any suitable means, for example compression screws 50 which communicate between flange 42 and portion 34 and bore 44 is coaxially aligned with a substantially equal diameter bore 52 which extends through the bottom of portion 34.

Centralizer arm 30 comprises an elongated vertical shaft portion 54 and a supporting and guiding arm portion 56. Antifriction tubular sleeves 58 and 60 having outer diameters thereof substantially equal to the diameters of bore 44 and 52 are coaxially and non-rotatably received within bores 44 and 52, respectively and are retained therein in any suitable manner. The inner diameters of sleeves 58 and 60 are substantially equal to the outer diameter of shaft 54 and in the final assembly of centralizer 26 shaft 54 extends coaxially through sleeves 58 and 60.

Upward movement of centralizer arm is prevented by means of a castle nut 62 threadably received on a lower end portion of shaft 54 which is spaced downwardly from the lowermost surface of portion 34. It is to be noted that to allow for the free rotation of arm 30, nut 62 is not tightened into compression with portion 34. Arm 30 is seated on the stationary casing member 28 by means of a seating portion 64 rigidly secured shaft 54 adjacent the upper end thereof. Seating portion 64 is of a generally circular transverse cross section and includes an upwardly extending circular depression 66 in the lower end thereof. Shaft 54 is coaxially received in depression 66 and extends downwardly therefrom. The diameter of depression is slightly greater than the outer diameter of seat 46 thereby enabling seating portion 64 to be cooperable with and rotatably seated on seat 46.

As shown in FIG. 4 supporting and guiding arm portion 56 includes; a diagonal section 68 having the lower end thereof rigidly secured to seating portion 64 adjacent the upper end thereof and extending upwardly and inwardly toward the longitudinal axis of drill guide frame 12 and an open U-shaped supporting and guide section 70 extending inwardly from the upper end of section 68. The innermost portion 72 of the opening in section 70 is of a generally circular configuration and in the supporting position of centralizer 26, as shown in FIG. 4, the central axis of portion 72 is in vertical alignment with the longitudinal axis of the drill guide frame 12. In operation a drill steel 22 is received with the opening in section 70 and seated in portion 72 for the supporting and guiding of the drill steel 22.

It can be readily seen from a review of the drawings and description as set forth hereinabove that the centralizer 26 will not interfere with the movement of the drill motor 20 along the drill guide frame 12 for when the drill motor 20 approaches the centralizer 26 the centralizer arm 30 is free to swing out of the path of the oncoming drill motor 20. As shown, centralizer arm 30 rotates ninety degrees with respect to the vertical axis through shaft portion 54 and in the final rotated position thereof centralizer arm 30 is substantially parallel the longitudinal axis of guide frame 12. When centralizer 26 is in the operational position thereof supporting aned guiding a drill rodv22 therein, centralizer arm 30 is substantially normal to the longitudinal axis of guide frame 12.

Casing portion 34 includes a pair of inwardly extending lug portions 74 therein adjacent the ends thereof and intermediate the upper and lower sides thereof. Lug portions 74 include bores 76 therethrough. Bores 76 are in axial alignment and an axis passing therethrough is substantially parallel to the longitudinal axis of guide frame 12. As shown in FIG. 3, an elongated piston rod 78 extends continuously through both bores 76 and the axial ends thereof extend into respective casing portion 36. A piston head 80 is in contact with each end of piston rod 78. Piston heads 80 slide within respective casing portions 36 and have suitable sealing means, such as rings 82 about the periphery thereof which sealingly engage the adjacent inner periphery of respective casing portions 36.

The reciprocable movement of the piston assembly results in the hereinabove described swinging movement of centralizer arm 30 by means of rack and pinion arrangement. The rack and pinion arrangement is best shown in FIGS. 3 and 4 and comprises a plurality of rack teeth 84 which are cut or formed in piston rod 78 intermediate the axial ends and which teeth 84 are in driving engagement with the teeth of a pinion gear 86 which is carried by shaft portion 54 intermediate the axial ends thereof. The piston assembly is pneumatically powered for the reciprocable movement thereof by means of a suitable source of pneumatic pressure fluid (not shown) which is in communication with each piston head 80 through bores 88 extending through each casing portion 36 at the outer ends thereof. As viewed in FIG. 3 to rotate the centralizer arm 30 to the position thereof parallel to the longitudinal axis of drill guide frame 12 fluid flows through the right bore 88 and acts on the right hand piston head 80 thereby resulting in the piston rod 78 moving to the left and the fluid in the left hand casing 36 being displaced by the left hand piston head and flowing out of the left bore. The movement of the centralizer arm 30 to the position thereof perpendicular to the longitudinal axis of drill guide frame 12 is opposite to the method described hereinabove. v

Inasmuch as the invention herein resides in providing a centralizer assembly adapted to swing out of the path of a drill motor thereby permitting the drill motor to advance therepast, various modifications can be made to the preferred embodiment described hereinabove without departing from the scope of the invention, for example: the pressure fluid for the reciprocable movement of the piston assembly may be hydraulic rather than pneumatic; guide frame 12 can be provided with a plurality of bores thereon such as the centralizer can be moved up and down on the side of the guide frame so that drills with different drill steel center lines can be accomodated; a plurality of centralizer assemblies of the present invention may be mounted on a single guide frame; bores can be provided on both sides of the guide frame'such that the centralizer may be mounted on either side of the guide frame the rotation of centralizer arm 26 can be more or less than 90, for example 60 to so long assuch rotation is sufficient to enable the drill motor 20 to pass thereby.; and the like. When moving the centralizer from one side of the guide frame support portion 40 is removed to index the arm into a proper tooth engagement which will provide for the arm continuing to swing away from the path of the drill.

What is claimed is:

1. In a rock drill assembly having an elongated drill guide frame and a centralizer assembly utilized for maintaining a drill steel string in a relative operating position, such a drill steel string having the longitudinal axis thereof spaced from said drill guide frame in a given direction, the improvement comprising: said centralizer assembly having a casing member supported by said drill guide frame; a drill steel guiding arm having one end thereof pivotally supported by said casing member for rotation about a pivot axis which extends generally in said given direction and is transversely spaced from the longitudinal extent of said drill guide frame and having the other end thereof of aconfiguration to engage such a drill steel in guiding relationship; and fluid operated means operable to rotate said arm about said pivot axis to selectively engage such a drill steel.-

2. A rock drill assembly as specified in claim 1 wherein said arm rotates approximately ninety degrees between positions of engagement and disengagement ithss chas r ll Ste 3. A rock drill assembly as specified in claim 1 wherein said means is operable from a pneumatic fluid pressure source.

4. A rock drill assembly as specified in claim 1 wherein said means includes a dual headed piston for double acting operation.

5. A rock drill assembly as specified in claim 4 wherein said means additionally includes a rack and pinion assembly for rotating said arm.

6. A rock drill assembly as specified in claim 5 wherein the rack of said rack and pinion assembly is integral with the drive shaft extending between a pair of piston heads.

7. A rock drill assembly as specified in claim 6 wherein said arm rotates in the range of 60 to 130 whefein the Pinion of Said a and assemblx is between positions of engagement and disengagement carried by said one end of said arm and said rack dI'lV- ingly engages said pinion for rotating said arm. with-siuch-gdfi-Ll-sliql" 8. A rock drill assembly as specified in claim 1 5 

1. In a rock drill assembly having an elongated drill guide frame and a centralizer assembly utilized for maintaining a drill steel string in a relative operating position, such a drill steel string being spaced from said drill guide frame in a given direction, the improvement comprising: said centralizer assembly having a casing member supported by said drill guide frame; a drill steel guiding arm having one end thereof pivotally supported by said casing member for rotation about a pivot axis which extends generally in said given direction and is transversely spaced from the longitudinal extent of said drill guide frame and having the other end thereof of a configuration to engage such a drill steel in guiding relationship; and fluid operated means operable to rotate said arm about said pivot axis to selectively engage such a drill steel.
 2. A rock drill assembly as specified in claim 1 wherein said arm rotates approximately ninety degrees between positions of engagement and disengagement with said drill steel.
 3. A rock drill assembly as specified in claim 1 wherein said means is operable from a pneumatic fluid pressure source.
 4. A rock drill assembly as specified in claim 1 wherein said means includes a dual headed piston for double acting operation.
 5. A rock drill assembly as specified in claim 4 wherein said means additionally includes a rack and pinion assembly for rotating said arm.
 6. A rock drill assembly as specified in claim 5 wherein the rack of said rack and pinion assembly is integral with the drive shaft extending between a pair of piston heads.
 7. A rock drill assembly as specified in claim 6 wherein the pinion of said rack and pinion assembly is carried by said one end of said arm and said rack drivingly engages said pinion for rotating said arm.
 8. A rock drill assembly as specified in claim 1 wherein said arm rotates in the range of 60* to 130* between positions of engagement and disengagement with said drill steel. 